1. Field of the Invention
This invention relates generally to molded plastic pails, buckets and similar containers having pivotable handles, and particularly to such a container molded from a plastic and having an integrally formed pair of pivotable handle members.
2. Description of the Prior Art
Many types of molded plastic pails and buckets are old in the art. The most common type include a generally cylindrical or tapered cylindrical body, flat bottom, and an outwardly projecting peripheral rim surrounding the open top of the receptacle region. A handle or bail, usually of metal or plastic, extends in a generally uniform semicircular curve between opposing side walls of the pail or bucket and is pivotably connected at each end to the pail or bucket. The bail is normally attached to the pail or bucket by bending or crimping the ends of the bail and inserting them through apertures in a boss or flange adjacent to the rim. The ends of the bail may be further crimped, rounded, or capped to prevent the bail from disengaging from the apertures. Representative examples of this type of container and handle assembly are shown in U.S. Pat. No. 4,997,098 to Buza; U.S. Pat. No. 3,977,563 to Holt; and U.S. Pat. No. 4,881,658 to Van Cucha.
Various designs have been developed incorporating an integral or unitary bail with the molded plastic pail or bucket in order to overcome the disadvantages associated with assembly, or to overcome structural disadvantages inherent in conventional pails and buckets.
Representative examples of pails and buckets incorporating unitarily or integrally molded plastic bails are shown in U.S. Pat. No. 3,310,088 to Hildebrandt; U.S. Pat. No. 3,730,382 to Heisler; U.S. Pat. No. 4,357,042 to Gall; and U.S. Pat. No. 4,380,304 to Anderson. Each of these references discloses a container having one semi-circular bail molded integrally with the container, and pivotably movable between a lowered position where the bail is substantially coplanar with the rim of the container and a raised position where the bail extends substantially vertically above the top of the container. The handles are either connected directly to the side walls of the pail or to molded lugs or bosses extending radially outward from the side walls. The handles are generally flat strips which crease at points or fold lines across which the handle may be pivoted upwardly, with some of the handles capable of twisting partially along their lengths as they are pivoted upwardly. Heisler '382 provides a bail with a substantially circular cross-section that twists longitudinally when pivoted upwardly, but which utilizes reinforcement fins or flanges directly adjacent to the side walls of the pail to prevent the bail from shearing upon excessive rotation or due to jerks or sudden pulls.
Another alternative method of forming an integrally molded pail bail is disclosed in U.S. Pat. No. 3,889,732 to Wilkins, which shows a pair of opposing semi-circular bails connected to the side walls of the pail by U-shaped lugs. The portions of the handles adjoining the lugs are flattened to provide a single crease point across which the handles will pivot upwardly, and are scored to form ligament hinges. The semi-circular bail segments are flattened to mate together throughout their entire length when both pivoted to their fully raised position above the pail.
Among the most notable disadvantages of the integrally molded pail bails discussed above are the formation of single crease points or fold lines required in order to permit the bails to be pivoted upwardly, and which also produce shear points along which the handle is substantially weakened and will tend to break unpredictably. These shear points will also lead to deterioration of the bail upon repeated use, and make the bails susceptible to failure when the pail is used in cold conditions or contains a frozen product. The use of a single flat handle which twists when pivoted upwardly or when a load is placed in the container increases the likelihood of handle breakage by further stressing any crease points or fold lines, and does not provide any backup if that single handle fails.